1. Field of the Invention
The present invention relates to a radio transmission apparatus, a radio receiving apparatus, a radio communication apparatus, a radio transmission method, and a radio receiving method.
2. Description of the Related Art
Recently, there is widely adopted the protocol of a radio communication system that is called 3G (3rd generation).
There are some developmental stages also in this 3G. The cellular phone that adopts the protocol that is called 3.5G or HSDPA in which the transmission rate is sped up further, as well as the original 3G that is adopted in FOMA and the like, has appeared, too. In addition, the protocol that is called Super3G or 3.9G is examined now.
The protocol in the radio communication system of group of this 3G is divided into two or more layers, and layer 2 of those layers is composed of three sub-layers of MAC (Medium Access Control), RLC (Radio Link Control) and PDCP (Packet Date Convergence Protocol).
FIG. 1 is a construction view of a protocol.
Layer 1 is a layer that is called a physical layer, and the layer 1 is a part which takes charge of an actual communication.
Layer 2, which is the superordinate position layer, is composed of three sub-layers of MAC, RLC and PDCP.
Here, the mass of one processing function arranged in one layer or one sub-layer is called entity (entity). The PDCP entity and the RLC entity correspond to each LCH (Logical Channel: logical channel) and exist by the
number of LCH to be used, and perform transmitting-receiving of PDU (Protocol Data Unit) having a one-to-one correspondence. Here, in the PDCP entity, the processing such as the ciphering of data is done in 3.9G (Super3G), and in the RLC entity, the processing such as the control of retransmission of data is done.
Moreover, in the MAC entity, PDU that has been forwarded from each RLC entity through each LCH is integrated into one PDU, and the integrated PDU is forwarded through TRCH (Transport Channel) to the layer 1 that is the subordinate position layer.
At the receiving side, the MAC entity divides the PDU, which is transferred from the layer 1 through the TRCH, into one or two or more PDU, and transfers the divided individual PDU through individual LCH to individual RLC entity.
Here, in individual PDU, the mechanism that information can be exchanged with the opposing side by giving not only the user data but also the control information necessary for the entity on the opposing side is being examined by 3GPP (3rd Generation Partnership Project).
FIG. 2 is a view showing an example of data flow where control information is given.
Here, in the RLC entity of LCH#1, header H and control information CONT are added to SDU (Source Date Unit) received from the PDCP entity, and it is sent to the MAC entity in form of new SDU. In the RLC entity of LCH#2, only the header H is added to SDU received from the PDCP entity, and it is sent to the MAC entity in form of new SDU.
In the MAC entity, SDU received from the RLC entity of LCH#1 and SDU received from the RLC entity of LCH#2 are integrated, and header H is added in addition, so that one PDU is formed and is transferred to the layer 1.
The layer 1 transmits on a radio basis to the PDU.
The control information CONT added in the RLC entity of LCH#1 is referred to by the associated entity at the receiving side, that is, the RLC entity of LCH#1 at the receiving side, but not referred to by the RLC entity of LCH other than LCH#1 at the receiving side, and entity of other layer or sub-layer, that is, the entity of the layer 1, the MAC entity, and the PDCP entity.
It is examined by 3GPP standardization to be able to give not only the user data but also the control information with the opposing entity to sending and receiving PDU, and, as a result, the exchange of the control information becomes possible between each entity. This is suitable when peculiar control information is exchanged between the opposing entities.
However, when it is intended that the control information of the same content, such as hand-over information and reset information, is transmitted or received not only between entities in which some LCH in the same sub-layer opposes, but all entities in the same sub-layer or all entities in layer 2, as for the current state, the control information on each entity will be given when PDU is made by each entity, and the control information spreads consequentially in all entities, but as sending and receiving PDU between the MAC entity and the layer 1, the size grows by the amount of the control information, and it imposes a burden on a radio transmission.
FIG. 3 is a view useful for understanding an example where the control information on the same content is transmitted to all entities of RLC sub-layer.
As shown in FIG. 3, at the transmitting side, in all of the RLC entities, header H and control information are added to the PDU and then transmitted to MAC entity. And, in the MAC entity, the header H is added and then transferred to the layer 1, and transmitted on a radio basis.
In this case, control information, which is added in the individual RLC entity, is referred to by RLC entity of the associated LCH on the opposing side. Thus, the control information is able to be delivered to all RLC entities on the opposing side. However, because two or more same control information will exist, the traffic increase of a radio communication might be invited.